1. Field of the Invention
The present invention relates to an image recording apparatus, such as a printer, a facsimile or a copier. The invention particularly relates to an image recording apparatus in which an upper unit case having an original reading portion is attached to be rotationally openable or closable to a lower unit case having a sheet feed portion and a recording portion, and in which the upper unit case can be slowly closed.
2. Description of the Related Art
Conventionally, various mechanisms have been proposed in which one side of the upper unit case is attached to be rotationally openable or closable via a hinge to a lower unit case, whereby the upper unit case is kept widely opened when conducting maintenance or paper jam handling.
For instance, Japanese Utility Model Registration No. 3093658 (see FIGS. 1 and 2) discloses a mechanism in which a stand member rotatably secured to a lower face of an upper unit case is faced within a receiving opening formed in an upper face of a lower unit case. Engaging claws provided on the bottom of the stand member are engaged at an edge of the receiving opening, so that the upper unit case is kept in an attitude at a constant opening angle. An elastic member provided on the lower side of the stand member is resiliently pressed around the edge of the receiving opening, whereby the rotation of the upper unit case is braked in an area where the upper unit case begins to be closed or ends to be opened.
With this configuration, the brake (braking) is not applied in a closing end area where the upper unit case approaches the lower unit case, so that the upper unit case may be rapidly closed to undergo a great impact.
In order to solve this problem, JP-UM-B-1-29815 (see FIGS. 3 and 6) discloses a mechanism in which an arcuate guide member (guiding member) projecting downwards on a side face of an upper unit case (cover) is formed with an arcuate guide groove. A shaft of a bolt at one side of a lower unit case (housing) is inserted through the guide groove, and the upper unit case is held in position at any rotation angle by clamping the guide member between a head of the bolt and a spring member. The upper unit case is urged upwards by a torsion spring disposed in the lower unit case at a closed position where the upper unit case is closed on the lower unit case.